Preheat the oven to 350°F. Line a large baking sheet with aluminum foil.

Add one layer of graham crackers to the baking sheet. If using the large 17x11 inch baking sheet, this will be 14 graham crackers.

Add the butter, brown sugar and sea salt to a medium saucepan and melt over low heat, stirring and scraping the bottom and sides of the pan often.

Turn up the heat and bring the mixture to a boil, and allow to boil for 2 minutes.

Remove from the heat and immediately stir in the vanilla and pecans.

Carefully pour the mixture over the crackers and spread it out with a silicone spatula.

Transfer the baking sheet to the oven and bake for 10 minutes.

Remove from the oven and allow to cool completely for 1-2 hours, then break into pieces.